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3.0L 12V rebuild and GTV6 conversion

Posted: Fri Apr 28, 2006 3:47 am
by David
Thought I would start a new thread for my next 3.0L conversion. I'll follow the conversion process as I detailed in the technical section. For you guys that do this for a living it is probably boring but many of us do this in our spare time and on somewhat limited budgets so this may help others wanting to do the same.

This is only my third Alfa V6 rebuild (2 X 2.5L) & (this 3.0L 12 V) and my second 3.0L (ex 164 12V) conversion into a GTV6 so I'm no expert.

This time I'm only slightly modifying the 3.0L but will be using Megasquirt with spark. My plan is to build new intake runners as per the last conversion but this time enlarge the 2.5 plenum intake runners, no AFM. no distributor (coil packs). I'll post some photos along the way so here's a start to the project.

. 2.5 flywheel has been lightened and the crank, rods & pistons balanced.
. Camshaft profile yet to be decided but probably similar to 164S
. Valves and seats have been done and the heads skimmed. I think they may have been previously machined so I'm a bit worried about the minimum head face to cam centre height.
. I'm using new standard genuine pistons and barrels.
. Tappet covers and plenum will be coated with VHT wrinkle black.
. 4mm flywheel spacer for the 2.5 flywheel

Questions????

1. Genuine Alfa big end bearings are no longer drilled for the the oil squirters on the con rods. Drilling is no problem as I've made a jig to do this. Should I drill these or not?

2. Is the factory recommended mimimum head height critical? Do I have to have the cam belt, etc installed to check this?

3. What coil packs have others used?

I'm sure to have more questions along the way. Here are some photos so far.

David

Posted: Fri Apr 28, 2006 4:47 am
by Dennis
Way to go, David! You won't regret fitting a 3.0, except for the sound the 3.0 is far superior.

But why don't you buy some HC pistons while you are at it? That way you'll have a real good base to start from and experience with cams and get optimum performance out of it. High comp pistons will give you the biggest boost in performance.....

Posted: Fri Apr 28, 2006 5:30 am
by Seb
Way to go man!

Will keep an eye on this thread. Did you ballance only the flywheel or with the crank? I never got that sorted on mine :(

Seb

Posted: Fri Apr 28, 2006 2:05 pm
by David
Dennis, High comp pistons would be great. Maybe I'll take that option when I rebuild my other 3.0L engine. I picked up the new Alfa piston & barrel kits and a complete genuine gasket set last year at a very good price so I want to make some use of these items.

Seb, The flywheel, crankshaft, front pulley, etc were balanced as a complete unit.

David

Posted: Fri Apr 28, 2006 9:33 pm
by FLETCH
Excellent ,perfect timming David,
I have spent the day today rearranging the garage ,making room for the 164 so now it is in there the motor is ready to come out,i will be full of questions in the next month or so.
cheers m8 8)

Posted: Tue May 02, 2006 1:10 am
by Jose_76
Thanks David!!

I guess I'm going to read carefully this thread for my next 164's 3.0 rebuild/conversion!! :wink:

Maybe you're making a new .doc with the whole process including MS and spark?? :D

Good Luck mate! :wink:

Posted: Tue May 02, 2006 2:17 am
by David
Jose,

I probably will add the rebuild process to the previous doc. I am working on the inlet runners at the moment, a bit different than the last conversion as I'm enlarging the 2.5 plenum runners to suit. Should have some pics in a few days when the welding is complete.

The oil pump is ready with the 3.0L drive shaft installed in the 2.5L pump.

Still have the cams to sort out and then check valve/piston clearance, etc.

I have the MS ECU ready but the MS spark will be interesting as I have not done anything along those lines before.

David

Plenum & Runners

Posted: Fri May 05, 2006 1:11 am
by David
I decided to go with the 2.5 plenum again as it makes the intake, throttle body, etc a lot easier. After a bit of hacksawing on the 164 plenum and the 2.5 plenum I had the 164 inlets welded to the 2.5 plenum. The 164 inlets have been reamed out to around 41mm.

Instead of mandrel bending the runners I did a cut and weld to acheive the required bend. the plenum and runners will be joined with silicone hose.

A cross section cut of the original 164 runners shows they are not much bigger than the 2.5 runners.

Pics of progress so far.

David

Runners

Posted: Fri May 05, 2006 1:17 am
by David
Runners

Posted: Mon May 08, 2006 12:28 am
by FLETCH
Nice work there David. 8)

what do you need to weld the plenum ? can you use a mig with different wire ?(never really thought about welding alloys).

Now for the big question to all reading this thread. i pulled the motor out of my 164 last night (never realised how much fluid an auto could hold,very messy :roll: ),and got the computer and loom out this afternoon,what other bit's will i be needing from the 164 before i part it out or dispose of it ?
are any of the brake parts usable on a GTV ?
Booster,master cylinder etc.
anything at all i could use?

cheers all. 8)

Posted: Mon May 08, 2006 1:03 pm
by Daniel
Fletch
Just make sure you have all of the relays and electricals attached to the computer loom (I didn't get the bracket to mount the coil and fuel pump relay and it got a little messy). If it has a 24mm brake master cylinder then definitely keep it (I'll buy it off you). I have also seen people use the front brake rotors with a set of caliper mounts to adapt to them but there are better setups.
I think I still have one 316SS flywheel spacer like the one I supplied to David for his conversion if you need one.
Keep us informed of the project.

Posted: Tue May 09, 2006 1:54 pm
by David
Fletch,

I can't take credit for the alloy welding. The hacksawing and welding the mild steel runners is about my limit. The alloy welding and the exhaust pipe for the runners cost me $85 AUS. With an air intake setup similar to my last conversion, the whole lot from the air filter to the intake manifolds will be around $200 which is pretty reasonable.

David

Posted: Tue May 09, 2006 10:56 pm
by FLETCH
Fair enough David,
i am still interested in finding out if it is possible to weld alloy with a mig and i guess alloy wire ?

Daniel, i will be needing a spacer,let me know if you want to part with it and how much? i pulled the master cylinder (22mm),booster and front disc's and calliper's off last night,thanks again for your info,i need as much as i can get :D

another question to all, can you put cams from a 2.5l in a 3l head ?
reason being the 3l i have is just a bog stock,and the 2.5l i will be taking out has good cams in it,so do they fit in ok(i am by no means a mechanic,just like a lot of the other alfa owners i have met i like to do as much mechanical work as i can myself )

also the extractors that are on my car at the moment should bolt up to the 3l ok ?

and lastly what are the power figures of all the different variations of alfa v6's?
cheers all 8)

Posted: Wed May 10, 2006 12:16 am
by Jose_76
Fletch, the stock headers on the 2.5 and 3.0 are the same. You can fit 2.5 cams on 3.0 without any problem, it's a direct bolt on, but they're not the same. I found the information about both cams and 3.0 ones are hotter.

Posted: Sun May 14, 2006 12:51 pm
by Daniel
Fletch, I forgot to have a look for that spacer over the weekend. Will have a look this week.
D